The Graphical User Interfaces - SCJD Exam with J2SE 5 - page 255

more flexible data display, a good table class would need additional methods and constructors
to fit within the paradigm of the MVC pattern. It so happens that the JTable fits incredibly well
into this pattern—so much so that the JTable actually defines its own model: the TableModel
interface.

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Note Many Swing components, such as the JTable and the JTree , implement their own MVC
architecture.

The TableModel
The TableModel is one of the easiest and most flexible ways to display a data set in a JTable .
Earlier in this chapter, the interaction between the Model and the View in the MVC pattern
was discussed in detail. As you may recall, the View is solely responsible for taking the data
contained in a Model object and converting it into a visual representation. The JTable
actually incorporates this part of the MVC pattern into its standard API. An implemented
TableModel interface acts as the Model in this case, and the JTable instance acts as the View.
The TableModel is essentially handed off to a JTable instance, and the table widget renders
the data model into the visual representation. The Model may be specified in the JTable
constructor:

JTable table = new JTable (TableModel model);

or set via the void setTableModel (TableModel model) instance method. Once the TableModel
is passed to the table instance, the JTable class literally takes care of the rest.
At this point, the JTable may seem like a snap to use. While the JTable is quite easy to
use, the bulk of the work for the developer comes in the task of implementing the TableModel
interface.
As with event listener interfaces, not all of the methods specified in the TableModel
interface are always necessary for a given data set. For instance, if a developer wanted to
implement a simple TableModel , it would be inefficient to have to provide implementations
for all the interface methods, such as removeTableModelListener(TableModelListener
modListener) . Thus, an adapter class is provided that functions in a manner similar to
event adapter classes. The AbstractTableModel class implements the TableModel interface
such that each method already has a default implementation. Therefore, extending the
AbstractTableModel class is usually the best starting point when creating a custom
TableModel .
In version 2.0 of the Denny's DVDs application, the DVDTableModel class is an extension
of the AbstractTableModel class. The DVDTableModel does not need to implement the
getColumnClass , removeTableModelListener , and addTableModelListener methods, so their
default implementations provided by the abstract implementation will suffice. All other
methods in the TableModel interface will be implemented.
First, notice the addition of the two member variables in the DVDTableModel class in
Listing 8-10.